package MyArrays;

public class test01 {
    public static void main(String[] args) {
        System.out.println(getCount(20));
    }
    public static int getCount(int num){
        if(num == 1){
            return 1;
        }
        if(num == 2){
            return 2;
        }
        if(num == 3){
            return 4;
        }
        return getCount(num-1) + getCount(num - 2) + getCount(num - 3);
    }
}
